San Bruno Police Chief Ed Barberini said four people were injured when a woman opened fire at the YouTube headquarters this afternoon. The woman believed to be the shooter was found dead in the building with what police are calling a “self-inflicted wound”.

The act is not believed to be related to terrorism.

At least one of the injured is reported to be in critical condition. Three patients from the shooting have been taken to the San Francisco General Hospital.

Panicked employees fled the YouTube building, in San Mateo county, located south of San Francisco. Some 1,700 people work at the YouTube HQ.

Reports over social media claim that some employees were barricaded inside, but were later evacuated.

Images broadcast on local TV stations showed employees leaving with their hands raised. Other footage appeared to show evacuees forming a queue before being individually frisked by police.

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